Sir Peter Bonfield promised a "rollercoaster ride" when he became chief executive of BT in 1996.

And, in terms of the BT's share price, that is precisely what his reign has delivered.

From a price of less than £4 when Sir Peter joined, BT stock clunked its way to a peak of more than £15 in December 1999, since when it has plunged and twisted back to current levels of around £5.

Sir Peter had warned observers: "Fasten your seatbelts".

But it is little wonder that investors who locked into BT holdings are questioning whether they have been taken for a ride, rather than enjoying one.

Computer pioneers

Sir Peter, who prides himself on a matter-of-fact manner, gained his 'estuary' accent from an upbringing in Hertfordshire.

But his interest in technology goes back at least to time at Loughborough University, from where he graduated with an engineering degree.

His early career included spells in some of the biggest names in the nascent computer industry, including Texas Instruments, with whom he served in the Far East, Europe and the US, STC and, from 1981, ICL.

He helped oversee ICL's transformation from a mainframe specialist into a computer networking pioneer, and in the 1990s into a leading PC manufacturer.

'Biggest test'

He had earned his CBE by 1989, long before he was snapped up by a flagging BT keen to tap his "international experience, his dedication to quality management, and his in-depth knowledge of the computing services industry".

But, ironically, it was in his international dealings, in the same US market which had proved his making two decades earlier, that Sir Peter first hinted he might struggle to fulfil the high expectations placed on him by City investors.

In 1997, Standard Life's Graham Wood spoke for many fund managers when he said that the "biggest test" for Sir Peter would be how he handled BT's plans to takeover US telecoms firm MCI.

The merger was designed, in Sir Iain Vallance's words, to create "one of the first great companies of the 21st century", which would deliver expansion on a global scale.

As it was, Sir Peter, using the excuse of shareholder pressure, lopped $4bn off BT's offer after MCI issued an earnings warning.

And MCI was snapped from beneath his nose by WorldCom.

Mounting debts

While BT has notched up considerable successes under Sir Peter's leadership, and seen its shares triple in price during the two years to the end of 1999, the firm has been criticised for not using its seemingly indomitable position in the middle of the decade to greater effect.

The company could have exploited advances in internet and mobile telephony technology, many analysts have said.

BT, while owning the successful Cellnet mobile phone arm, has a stock market valuation less than a third that boasted by Vodafone.

And, while it seems hard to believe today, when BT is among firms most troubled by borrowings incurred buying 3G mobile phone licences, the firm was virtually debt free at the time the MCI deal collapsed.

Sharp edge?

According to newspaper reports, Sir Peter keeps in his office a samurai sword given to him by Fujitsu.

Earlier this year, when investors lost their patience, BT's chairman Sir Iain Vallance was forced to go.